Wrapping member for a glass substrate for FPD and a method of transferring a glass substrate for FPD

ABSTRACT

A wrapping member for wrapping a glass substrate to be used in production of a FPD such as a liquid crystal display and a plasma display and a method of transferring a glass substrate for FPD, in which the wrapping member for wrapping either one or both of the surfaces of the glass substrate for FPD before transfer is made of a water-soluble film material dissolved in water, so that preprocessing of each of the glass substrates in the production line of the FPD may be simplified and so that the outer shape of a package formed by packing the glass substrates in a transfer box and a lid for closing the transfer box is reduced to an extent enabling a plurality of the glass substrates to be transferred at a high efficiency.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a wrapping member for a glass substrate used for the production of a FPD (a Flat Panel Display) such as a liquid crystal display and a plasma display, and relates to a transferring method of a glass substrate for FPD. More, particularly, the present invention relates to a wrapping member for a glass substrate for FPD in which by wrapping the glass substrate or substrates with a water-soluble film, processing of the glass substrates and the wrapping member in the production line of FPDs can be simplified as well as reducing of the outer appearance dimension of the transferred packages can be accomplished thereby making it possible to transfer the glass substrates at a high efficiency, and to a method of transferring the glass substrates for FPD.

2. Description of the Related Art

Hitherto, in transfer of glass substrates used for the production of FPDs such as a liquid crystal display and a plasma display, a transfer box as shown in FIG. 6 has been employed. This transfer box 1 is produced so as to contain therein a plurality of glass substrates arranged to maintain their standing positions, and consists of a box-like body portion 2 made of light-weight and strong material such as polypropylene foam and a lid member 3 for covering the opening of the body portion 2 which are brought into a fixed condition by two rubber or gum bands 4. On the left and right side faces of the interior of the body portion 2, cushion members 6 for fixedly keeping the glass substrates 5 for FPD by sandwiching the marginal portions of the substrates are arranged as shown in FIG. 7. On the inside face of the cushion member 6, a plurality of protruding portions 7 are formed as shown in a partial enlarged view “P” of FIG. 7, and between every two protruding portions 7 and 7 gaps 8, each having the width thereof corresponding to the thickness of the glass substrate 5, have been formed. In a gap 8 formed between the every adjacent two protruding portions 7 and 7, the glass substrate 5 is fitted in such a manner that the margin of the glass substrate 5 is fixedly sandwiched by the adjacent two protruding portions 7 and 7. As a result, a plurality of glass substrates 5 is stored and juxtaposed in the interior of the transfer box 1 while being held in a vertically standing position, respectively. The above-described transferring method is typically disclosed in Japanese Unexamined (Kokai) Patent Publication No. 7-285611.

Nevertheless, the described transfer box 1 with the respective gaps 8 for fixedly fitting the glass substrates 5 must have suffered from an inconvenience as described below. That is to say, in order to prevent the glass substrates 5 from being damaged due to mutual contact of the neighboring glass substrates if the glass substrates 5 were subjected to bending during the transfer of the box 1 with the glass substrates 5 stored therein, respective gaps 8 of the transfer box 1 should be formed and arranged to define a predetermined distance “g₀” between the two neighboring gaps 8 when it is measured at the centers thereof, as shown in a partial enlarged view “P” of FIG. 7. For example, when the glass substrates 5, each of which is dimensioned to have 1100 mm width×1300 mm height and a thickness equal to or less than 1 mm, the protruding portions 7 must have been formed so that the distance “g₀” between the neighboring gaps 8 is approximately 25 mm. Therefore, as shown in FIG. 6, when the transfer box 1 is provided to store therein 20 sheets of glass substrates 5 for FPD, the outer dimension of the transfer box 1 is approximately 1200 mm width×1410 mm height×720 mm depth and, accordingly the entire size of the transfer box 1 could be a considerable large.

On the other hand, in recent years, as a glass substrate for producing a FPD having a large screen, there has been provided a glass substrate having for example, 1300 mm width×1500 mm height, 1500 mm width×1800 mm height, or 1900 mm width×2100 mm height. Nevertheless, the larger is the size of the glass substrate, the greater must be the bending of the glass substrate. Thus, to prevent the glass substrates 5 juxtaposed in the transfer box 1 from coming in contact with one another, the distance g₀ between the neighboring gaps 8 must be further increased, and therefore the depth “D” of the transfer box 1 must be increased. Namely, the volume of the transfer box 1 must be increased depending on an increase in the size of the glass substrate 5 and accordingly, the outer size of the transfer box 1 must be larger resulting in making it difficult to obtain an increased efficiency in the transfer of the transfer box 1 with the glass substrates therein.

In this connection, as a method of reducing the outer size of the glass substrates for FPD after they are completely wrapped by the wrapping material, there has been provided a method in which, as shown in (A) of FIG. 8, a thin plastic film 9 is interposed between every two of the glass substrates 5 as a spacer for protecting the surface of each glass substrate 5 before the glass substrates 5 are packed. However, in this method, a specified process for taking every one of the glass substrate 5 out of the stack of the glass substrates 5, as shown in (B) of FIG. 8 and for removing each thin plastic film 9 from the surface of the glass substrate 5, as shown in (C) of FIG. 8 has been required during processing of the glass substrates 5 on the production line for producing the FPD. Further, during removing of the thin plastic film 9 by peeling, static electricity might occur causing attaching of fine and minute foreign matters 10 such as dust on the surface of the glass substrate 5, as shown in (D) of FIG. 8 and therefore, a lot of time have been often needed for cleaning the glass substrate 5. Moreover, after heeling of the thin plastic film 9 from the surface of the glass substrate 5, there might have often occurred that adhesive 11 is left on the surface of the glass substrate 5 as shown in (D) of FIG. 8. Therefore, in such case, it has been needed to completely remove such residual adhesive 11 from the surface of the glass substrate 5, which renders a pretreatment process of the glass substrate 5 for FPD rather cumbersome. In addition, since the plastic films 9 removed from the surface of respective glass substrates 5 during the step shown in (C) of FIG. 8 must have been legally property disposed as industrial wastes, additional time and expense must have been spent for the waste disposal.

SUMMARY OF THE INVENTION

Therefore, to overcome the above-described problems encountered by the conventional art, an object of the present invention is to provide a wrapping member for a glass substrate for FPD, which enables it to simplify the processing of the glass substrates and the wrapping member on the production line of the FPD, and to reduce the outer size of the wrapped glass substrates thereby allowing the glass substrates to be transferred at a high efficiency.

Another object of the present invention is to provide a method of carrying out such a highly efficient transfer of the glass substrates for FPDs.

To achieve the above objects, in accordance with one aspect of the present invention, there is provided a wrapping member for a glass substrate for FPD, which wraps either one or both of the surfaces of the glass substrate for use in production of a FPD in a form suitable for being transferred, and is characterized in that the wrapping member is made of a material, which comprises a water-soluble film able to be dissolved in water.

Due to the above-described constitution of the present invention, the wrapping member used for wrapping the glass substrate for FPD can be dissolved in the water without becoming industrial wastes. Therefore, wrapping of the glass substrate with the water-soluble film can simplify the processing of respective glass substrates and the wrapping member on the production line of the FPD and additionally, reduce the outer size of the glass substrate in its wrapped condition for transfer thereby allowing the wrapped glass substrate to be transferred at a high transferring efficiency.

The above water-soluble film may be made of denatured polyvinyl alcohol. Owing to this, it is possible to adjustably change a temperature at which the water-soluble film is dissolved and the solving speed of the water-soluble film, depending on the mode of use of the water-soluble film and accordingly, dissolving condition of the water-soluble film may be freely selected as required. Therefore, the processing of the glass substrate and the wrapping member conducted on the production line of the FPD can be simplified.

The method of transferring glass substrates for FPD in accordance with another aspect of the present invention is characterized by comprising the steps of:

laminating a water-soluble film soluble in water onto either one or both of surfaces of each of the glass substrates;

admitting the glass substrates in a transfer box via an open end thereof to be stored therein in a manner such that they are superposed on each other; and

covering the open end of the transfer box with a lid to form a packed transfer box with the glass substrates stored therein, so that the packed transfer box is subjected to a transferring process.

When the above-mentioned method is carried out, either one or both of the surfaces of each glass substrate for FPD is laminated with the water-soluble film, and a plurality of the glass substrates, each being laminated with the water-soluble film, is stored in the transfer box in a condition such that they are superposed one another. Then, the transfer box is closed by covering the open end of the transfer box with the lid so as to form a packed transfer box with the glass substrates stored therein, and the packed transfer box is subjected to the transferring process. Owing to this method, the outer size of the packed transfer box can be small enough for being transferred at a high transferring efficiency.

Further, the above-mentioned transfer box and the lid are preferably made of material having hydroscopic property. Owing to this hydroscopic property of the material of the transfer box and the lid, the transfer box together with the lid may absorb the humidity in the atmosphere, so that solving of the water-soluble film may be prevented. Accordingly, during transferring of the glass substrates in the transfer box, the glass substrates can be always kept in a condition where the glass substrates within the transfer box are prevented from coming in contact with one another and therefore the surfaces of the glass substrates may be protected against damage.

Further, the transfer box and/or the lid may be provided with drying agent or desiccant in the inside thereof. Thus, any humidity contained within the transfer box and the lid may be absorbed by the drying agent or the desiccant, so that solving of the water-soluble film during the transferring of the glass substrates in the transfer box may be prevented. Therefore, during transferring of the glass substrates in the transfer box, the glass substrates can be always kept in a condition where the glass substrates within the transfer box are prevented from coming in contact with one another and therefore the surfaces of the glass substrates may be protected against damage.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view, in part broken away, of a transfer box and a lid, illustrating a state where a plurality of glass substrates for FPDs are wrapped and packed in the interior of the transfer box by the use of wrapping member according to the present invention;

FIG. 2 is a schematic and explanatory view of the processing steps, in which (A) through (D) illustrate how the steps for processing each glass substrate for FPD as shown in FIG. 1 are conducted for the production of the FPD;

FIG. 3 is a schematic and explanatory view of the wrapping steps, in which (A) through (D) illustrate how the steps for wrapping the upper surface of each glass substrate for FPD with a water-soluble film and for packing the wrapped glass substrates in the interior of the transfer box and the lid are conducted for permitting the packed glass substrates to be subjected to the transferring process;

FIG. 4 is a schematic view of the wrapping steps, in which (A) and (B) illustrate how the wrapping of both of the upper and lower surfaces of each of the glass substrates for FPD with the water-soluble film is processed;

FIG. 5 is a cross-sectional view of the glass substrate for FPD, illustrating the state where the glass substrate is entirely wrapped with a water-soluble film;

FIG. 6 is a perspective view of a transfer box for storing therein glass substrates for FPD, according to the prior art;

FIG. 7 is a plan view, in part broken away, of the transfer box shown in FIG. 6; and,

FIG. 8 is a schematic and explanatory view of the processing steps, in which (A) through (D) illustrate how the steps for processing the glass substrates wrapped with the wrapping member according to the prior art are conducted in the production line of the FPD.

DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

Referring to FIG. 1, which illustrates a transfer box 12 with a lid 13 covering an open end of the box 12, a plurality of glass substrates 5 for FPDs are stored and packed in the transfer box 12 covered by the lid 13, by the employment of a wrapping member according to the present invention. The wrapping members 14 are respectively provided as a thin film for protecting the surfaces of each the glass substrates 5 for FPD, and as shown in a partially enlarged view “Q” of FIG. 1, one wrapping member 14 is interposed between the respective upper and lower glass substrates 5 superposed one another. Owing to this interposition of the wrapping members 14, without using of the transfer box 1 of the prior art as shown in FIG. 6, a plurality of glass substrates 5 for FPD may be stored in the interior of the transfer box 12 and the lid 13 as shown in FIG. 1, and can be transferred. Since the transfer box 12 and the lid 13 may have a capacity thereof sufficient for storing a plurality of glass substrates 5 placed to be superposed one another, the outer dimension of the transfer box 12 and the lid 13 after packing up the superposed glass substrates 5, particularly, the height “h” of the package formed of the transfer box 12 and the lid 13 mated together for containing therein the glass substrates 5 can be prevented from becoming unexpectedly large. Thus, even when the glass substrates 5 having large sizes such as, for example, 1300 mm width×1500 mm height, 1500 mm width×1800 mm height, and 1900 mm width×2100 mm height, are to be transferred, the height “h” of the package obtained from packing any of such large glass substrates 5 by the use of the transfer box 12 and the lid 13 does not cause any appreciable change. Therefore, the transfer of the glass substrates 5 for FPD can be carried out at a high efficiency.

At this stage, in the present invention, the above-mentioned wrapping member 14 is made of a water-soluble material, i.e., a water-soluble film that can be dissolved in water. The water-soluble film 14 is a membrane material made of denatured polyvinyl alcohol and therefore, it is possible to adjust dissolving condition of the water-soluble film 14 depending on a change in the mode in which the film 14 is used. Namely, since the dissolving speed of the water-soluble film 14 changes in response to a change in the water temperature, the thickness of the film 14, and dissolving method adopted, any arbitrary dissolving condition can be selectively set as required. Thus, the glass substrates 5 transferred as a package packed by the transfer box 12 and the lid 13, and the water-soluble film 14 as the wrapping member can be simply processed on the production line of the FPD. Namely, from a plurality of glass substrates 5 as shown in (A) of FIG. 2, every sheet of glass substrate 5 in a state where the water-soluble film 14 is attached to the surface thereof as shown in (B) of FIG. 2 is withdrawn one after another. Subsequently, every drawn glass substrate 5 is in succession immersed in water held in a water vessel 15 as shown in (C) of FIG. 2. As a result, the water-soluble film 14 is dissolved in the water vessel 15 by the time lapse of less than several tens of seconds. For example, when the water-soluble film 14 having 20 micrometers thick is immersed in water at 20° C., the water-soluble film 14 can be dissolved in a time equal to or less than 20 seconds. Then, as shown in (D) of FIG. 2, the glass substrate 5 having no water-soluble film 14 left is taken out of the water vessel 15 so as to be transferred to the next processing stage. Therefore, differing from the conventional case as shown in (A) through (D) of FIG. 8 where the glass substrate 5 was protected by wrapping with the plastic film 9 according to the prior art, no process for removing the spacer by peeling is required.

Therefore, the preprocessing of the glass substrates 5 and the processing of the water-soluble film 14 can be simplified. Moreover, since the water-soluble film 14 different from the conventional plastic film 9 is excellent in its hydrophilicity, it cannot be electrified by static electricity. Accordingly, any dust and other foreign matters such as paper powder and the like does not attach to the surface of the glass substrate 5 and thus, the preprocessing of the glass substrate 5 can be prevented from becoming cumbersome. Further, since only preparation of the water vessel 15 for dissolving the water-soluble film 114 is required, and since no device or apparatus for removing the spacer is required, it is possible to curtail expense for the facility investment necessary for processing the glass substrates 5. Furthermore, the water-soluble film 14 is finally dissolved in water to be separated into carbon dioxide and water, and therefore generation of industrial wastes can be suppressed. Since the water-soluble film 14 does not contain therein any halogen element such as chlorine, it can be wasted with reduced adverse affect on the global environment in comparison with the employment of the ordinary plastic film.

The water-soluble film 14 described in the foregoing may be embodied by, for example, a product manufactured and sold under the name of “Hi-Selon: the registered trademark in Japan” by the Nippon Synthetic Chemical Industry Co., Ltd. that is one of the chemical industries in Japan. It should be noted that the water-soluble film 14 exhibits excellent properties as a wrapping material such as good mechanical properties including an excellent initial coefficient of elasticity, and an improved tensile strength and stretchability, and a heat-seal strength. Further, since the water-soluble film 14 can be easily either severed mechanically or cut by melting, it can be easily laminated onto the surface of each of the glass substrates 5 Now, the description of a method of transferring a plurality of glass substrates 5 packaged in the interior of the transfer box 12 and the lid 13 by the employment of the above-described water-soluble 14 will be provided hereinbelow with reference to the illustration of FIG. 3.

Referring first to (A) of FIG. 3, the water-soluble film 14 is placed in the form of a roll wounded around a core member 16 in a condition where a rear face of the film 14 is coated with a hot-melt type adhesive. The hot-melt type adhesive should preferably be excellent in a dispersing faculty into water and dissolving faculty in water and desirably, those disclosed in e.g., Japanese Unexamined (Kokai) Patent Publication No. 5-4853 and Japanese Unexamined (Kokai) Patent Publication No. 2002-173655 could be used. It should be understood that this type of adhesive having excellent dissolving faculty in water can be easily dissolved in the water vessel 15 shown in (C) of FIG. 2 during dissolving of the water-soluble film 14 within the same water vessel 15, and therefore the adhesive is not left to form no undesirable residue on the surface of the glass substrate 5 when the glass substrate 5 is taken out of the water vessel 15. As a result, the preprocessing step of the glass substrates 5 on the production line of the FPD can be simplified.

Then, the roll of the water-soluble film 14 as shown in (A) of FIG. 3 is rotated in a direction indicated by an arrow “A” so that an extreme end of the water-soluble film 14 is fed and delivered in a direction indicated by an arrow “B” until it is superposed on the upper surface of the glass substrate 5 for FPD from the leading to trailing ends of the glass substrate 5. Subsequently, the water-soluble film 14 together with the glass substrate 5 are supplied so as to be sandwiched between heating rollers 17 and 18 rotating in mutually reverse directions indicated by arrows “C” and “D”. Thus, the pair of heating rollers 17 and 18 rotating in the reverse directions applies heat to both the water-soluble film 14 and the glass substrate 5, and as a result, the adhesive coated on the rear face of the water-soluble film 14 melts thereby permitting the water-soluble film 14 to adhere onto the upper surface of the glass substrate 5. The water-soluble film 14 is then cut at the trailing end of the glass substrate 5 so that the film 14 is laminated on the upper surface of the glass substrate 5 as shown in (B) of FIG. 2.

Subsequently, the glass substrates 5 for FPD laminated with the water-soluble film 14, respectively, are placed in succession in the interior of the transfer box 12 in a condition such that they are superposed on one another within the transfer box 12 as shown in (C) of FIG. 3. As shown in (D) of FIG. 3, when a predetermined number of the glass substrates 5 are stored in the superposed condition, the transfer box 12 is covered with the lid 13 to form a package in which a predetermined number of glass substrates 5 are packaged within the transfer box 12 and the lid 13 as shown in FIG. 1. The package thusly formed to contain therein the predetermined number of the glass substrates 5 is transferred from a given position to another given position.

It should here be understood that the transfer box 12 and the lid 13 as shown in FIG. 1 and (D) of FIG. 3 are desirably made of a material having appreciably high hygroscopicity such as cardboard, polypropylene foam, and wood. Thus, as the transfer box 12 and the lid 13 can absorb the moisture component in the air, any dissolving of the water-soluble film 14 can be prevented during transferring of the package. This fact ensures that the glass substrates 5 for FPD in the package of the transfer box 12 and the lid 13 are kept in a state where any direct contact of the glass substrates 5 within the package can be prevented during transferring of the package, and the surfaces of the respective glass substrates 5 for FPD are protected against damage.

Further, as shown in a partial enlarged view “Q” of FIG. 1, the inside wall of the transfer box 12 may be provided with a suitable desiccant 19 in the form of a sheet. Thus, the desiccant 19 can absorb any moisture component in the interior of the transfer box 12 and the lid 13, so that the water-soluble film 14 can be prevented from being dissolved during transferring of the glass substrates 5. This fact again ensures that the glass substrates 5 for FPD in the package of the transfer box 12 and the lid 13 are kept in a state where any direct contact of the glass substrates 5 within the package can be prevented during transferring of the package, and the surfaces of the respective glass substrates 5 for FPD are protected from being damaged. Of course, the desiccant provided for the transfer box 12 and the lid 13 may have any suitable form if it could successfully absorb the moisture component within the transfer box 12 and the lid 13.

According to the foregoing description, an explanation of the embodiment was provided in which the water-soluble film 14 functioning as a spacer member is laminated onto the upper surfaces of respective glass substrates 5. However, the present invention should not be limited to only such embodiment, and therefore the water-soluble film 14 may be embodied to be applied to both the upper and lower surfaces of each glass substrate 5 according to the steps illustrated in (A) and (B) of FIG. 4. Also, as shown in FIG. 5, in a further embodiment, each of the glass substrates 5 may be wholly enveloped by the water-soluble film 14. In the described latter two cases, the upper and lower surfaces of the glass substrate 5 for FPD can be protected against damage. Moreover, since the protection of both the upper and lower surfaces of the glass substrate 5 for FPD does not cause any substantial increase in the outer size o f each glass substrate 5, transferring of the glass substrates 5 at a high efficiency can be surely achieved. Also, the processing of the glass substrates 5 on the production line of the FPD can be simplified with certainty.

Although the present invention has been described in relation to the preferred embodiments thereof, it should be understood that various changes and modifications will occur to a person skilled in the art without departing from the scope and spirit of the invention as claimed in the accompanying claims. 

1. A wrapping member for wrapping either one or both of surfaces of a glass substrate for use in production of a FPD in order to permit the glass substrate to be transferred, wherein said wrapping member is made of a material comprising a water-soluble film dissolved in water.
 2. The wrapping member according to claim 1, wherein said water-soluble film comprises a film member made of denatured polyvinyl alcohol.
 3. A method of transferring a glass substrate for FPD comprising the steps of: laminating a water-soluble film dissolvable in water onto either one or both of surfaces of a glass substrate for use in production of a FPD; admitting said glass substrate for FPD laminated with said water-soluble film in a transfer box in a condition where respective said glass substrates are superposed one another within said transfer box; and covering said transfer box with a lid to form a package to be transferred.
 4. The method according to claim 3, wherein said transfer box and lid to be transferred are made of a material having hygroscopicity.
 5. The method according to claim 4, wherein said transfer box and lid to be transferred are provided with desiccant arranged in the inside of at least one of said transfer box and said lid.
 6. The method according to claim 3, wherein said transfer box and said lid to be transferred are provided with desiccant arranged in the inside of at least one of said transfer box and said lid. 